Spacer fabrics and methods of making the same

ABSTRACT

A spacer fabric and methods of making the same comprising: knitting first and second yarns to form a knit structure, the first yarn defining mirror image knit and tuck patterns on at least the first and second courses and the second yarn defining mirror image knit and miss patterns on at least the third and fourth courses to comprise a plurality of concave portions in facing opposition to a plurality of convex portions, the concave and convex portions defining void spaces having a substantially double convex cross section, wherein the first yarn has low thermal shrinkage and the second yarn has high thermal shrinkage, and heating the knit structure at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension wherein the second yarn shrinks more than the first yarn in the at least one dimension when heating the knit structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 16/482,607 filed on Jul. 31, 2019, which is a 371 National Phase Entry of International Patent Application No. PCT/US2018/016081 filed on Jan. 31, 2018, which claims the benefit of U.S. Provisional Patent Application No. 62/453,147 filed on Feb. 1, 2017, with the United States Patent and Trademark Office, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to spacer fabrics and in particular to knitted spacer fabrics and methods of making the same.

BACKGROUND OF THE INVENTION

Spacer fabrics have been used as components of various products, ranging from footwear to costumes to backpacks. In conventional spacer fabrics, two separate fabrics (which may be referred to as a top fabric and a bottom fabric) are joined by fibers or filaments in a “sandwich” like construction, in which the top fabric and bottom fabric are spaced apart from one another by the intervening fibers or filaments. The intervening fibers or filaments typically have a low density, such that the region or space between the top fabric and the bottom fabric consists largely of air or empty space. However, some prior spacer fabric constructions provide a limited resistance to compression and/or provide only a single compressive resistance throughout the fabric. Some spacer fabrics can also require expensive, complicated, or time-consuming manufacturing processes. Therefore, there exists a need for improved spacer fabrics and improved methods of making spacer fabrics, including for applications requiring an increased compressive resistance and/or a varying compressive resistance.

SUMMARY OF THE INVENTION

Spacer fabrics and methods of making the same are described herein. Such fabrics can provide one or more advantages compared to other fabrics. For example, in some instances, the spacer fabrics described herein provide improved compression resistance, strength, durability, and/or cushioning. Spacer fabrics described herein can also provide nonuniform or varying properties across one or more lateral dimensions of the fabric. For instance, in some embodiments, a spacer fabric described herein comprises a plurality of zones of differing compression resistances. Such zones can correspond to a pressure map of the spacer fabric during use in an end application, such as a seating application or a footwear application. Moreover, in certain cases, spacer fabrics described herein incorporate electrically and/or thermally conductive fibers, yarns, or filaments for providing fabrics that can be heated or cooled, perform diagnostics, and/or massage portions of a user's body during use. Additionally, methods described herein can provide or form a spacer fabric in a more efficient and/or cost-effective manner compared to some other methods.

In one aspect, a method of making a spacer fabric is provided. Such a method, in some cases, comprises knitting a first yarn, filament, or fiber and a second yarn, filament or fiber to form a knit structure, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions. The concave portions and the convex portions define void spaces having a substantially double convex cross section. Further, the first yarn, filament, or fiber is a low thermal shrinkage yarn, filament, or fiber, and the second yarn is a high thermal shrinkage yarn, filament, or fiber, where “low” and “high” are understood to be relative terms, as described further hereinbelow. The method further comprises heating the knit structure at a temperature sufficient to cause the second yarn (or filament or fiber) to shrink by at least 10% in at least one dimension. Moreover, the second yarn (or filament or fiber) shrinks more than the first yarn (or filament or fiber) in the at least one dimension during the step of heating the knit structure. In some embodiments, the second yarn (or filament or fiber) shrinks by 10%-90% in the at least one dimension during the step of heating the knit structure, based on an original size of the second yarn (or filament or fiber) in the at least one dimension prior to the step of heating the knit structure. Further, in some cases, the second yarn (or filament or fiber) shrinks at least two times as much as the first yarn (or filament or fiber) in the at least one dimension during the step of heating the knit structure.

Moreover, the step of heating the knit structure can increase a size of the void spaces in a thickness direction of the fabric. For example, in some embodiments, the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 100%.

A method described herein can further comprise forming a knit structure from one or more additional yarns, in addition to the first yarn and the second yarn. Generally, “n” additional yarns may be used to form a knit structure described herein, wherein n is not particularly limited (e.g., n can be equal to 1, 2, 3, 4, or 5, or n can be equal to any integer between 1 and 100). In some cases, for example, a method described herein further comprises forming a knit structure from a third (or nth) yarn in addition to the first yarn and the second yarn (or in addition to the previously recited [n−1] yarns). The third yarn (or nth yarn) can differ from the first yarn and the second yarn (or from one or more of the [n−1] previously recited yarns). For example, in some cases, the third yarn (or nth yarn) is a thermally fusible yarn. The third yarn (or nth yarn) can be fusible at the temperature of the step of heating the knit structure. Similarly, a method described herein can further comprise forming a knit structure from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn. The fourth yarn can differ from the first yarn, the second yarn, and the third yarn. For example, the fourth yarn can have a color, texture, denier, and/or elasticity that differs from the color, texture, denier, and/or elasticity of the first yarn, the second, yarn, and/or the third yarn. It is again to be understood that methods described herein are not limited to the use of 3 or 4 differing yarns. Instead, n yarns or yarn types may generally be used, and then yarns or yarn types may be the same or different from one another in a variety of ways, including those described above.

Moreover, a spacer fabric described herein, after heating, can comprise a plurality of zones having differing properties. For instance, in some cases, the spacer fabric, after heating, has or exhibits different compression resistances in a thickness direction of the fabric (where the thickness direction may be denoted as the z direction). In such instances, it is to be understood that the compression resistance of the fabric varies as a function of one or both lateral dimensions of the fabric (where the lateral dimensions or directions of the fabric may be denoted as the x direction and the y direction). Moreover, a spacer fabric formed by a method described herein can have one or more first zones of low compression resistance and one or more second zones of high compression resistance, where the terms “low” and “high” are understood to be relative to one another. For example, the first zones, in some embodiments, have a compression resistance of no more than 30 psi, and the second zones have a compression resistance of at least 50 psi. Additionally, in some instances, the locations of the first and second zones can be determined based on a pressure map of the fabric when in use in an end application. For example, the end application can be a seating application, a footwear application, or any other application not inconsistent with the objectives of the present disclosure.

Methods described herein can be carried out in any manner not inconsistent with the objectives of the present disclosure as described further hereinbelow.

In a further aspect, spacer fabrics are described herein. In some embodiments, a spacer fabric described herein comprises a knit structure formed from a first yarn and a second yarn, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces. The void spaces can have double convex or substantially double convex cross sections. Moreover, the first yarn can comprise a low thermal shrinkage yarn and the second yarn can comprise a high thermal shrinkage yarn. Again, the terms “low” and “high” are to be understood to be relative to one another. In some cases, for example, the second yarn shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C. Further, in some embodiments, heating the knit structure at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension will increase a size of the void spaces in a thickness direction of the fabric.

Moreover, in some cases, a spacer fabric described herein, when unheated, is flat or substantially flat. Additionally, in some embodiments, a thickness of the fabric (e.g., in the z direction) increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.

As described above, knit structures described herein can be formed from one or more yarns in addition to the first and second yarns. Up to “n” additional yarns may be included in a knit structure described herein. For example, in some embodiments, a knit structure is formed from a third yarn in addition to the first yarn and the second yarn, and the third yarn differs from the first yarn and/or the second yarn. In some cases, the third yarn comprises a thermally fusible yarn. Moreover, in some such instances, the third yarn may be fusible at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension. Similarly, in some cases, a knit structure of a fabric described herein may be formed from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn. Such a fourth yarn can differ from the first yarn, the second yarn, and/or the third yarn. For example, the fourth yarn can have a color, texture, denier, and/or elasticity that differs from the color, texture, denier, and/or elasticity of any of the first yarn, the second, yarn, and/or the third yarn.

Additionally, the knit structure of a fabric described herein, in certain embodiments, is a unitary knit structure. Moreover, in some embodiments, a fabric described herein comprises a plurality of zones having different compression resistances in a thickness direction of the fabric. For instance, the fabric can comprise one or more first zones of low compression resistance and one or more second zones of high compression resistance. In some such cases, the first zones can have a compression resistance of no more than 30 psi and the second zones can have a compression resistance of at least 50 psi. Further, the locations of the first and second zones can correspond to a pressure map of the fabric when in use in an end application. For example, in some cases the fabric forms a portion of a seat or seat back. Alternatively, the fabric can form a portion of footwear.

In a preferred embodiment, a method of making a spacer fabric comprising: knitting a first yarn and a second yarn to form a knit structure, the first yarn defining a knit and tuck pattern on at least a first course and a mirror image pattern on at least a second course and the second yarn defining a knit and miss pattern on at least a third course and a mirror image on at least a fourth course, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section, and wherein the first yarn is a low thermal shrinkage yarn and the second yarn is a high thermal shrinkage yarn; and heating the knit structure at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension wherein the second yarn shrinks more than the first yarn in the at least one dimension during the step of heating the knit structure.

In a further embodiment, the method wherein the second yarn shrinks by 10% to 90% in the at least one dimension during the step of heating the knit structure based on an original size of the second yarn in the at least one dimension prior to the step of heating the knit structure.

In a further embodiment, the method wherein the second yarn shrinks at least two times as much as the first yarn in the at least one dimension during the step of heating the knit structure.

In a further embodiment, the method wherein the step of heating the knit structure increases a size of the void spaces in a thickness direction of the fabric.

In a further embodiment, the method further comprising at least a third yarn, said at least third yarn defined in at least a fifth course having a knit, miss, or tuck pattern and at least a sixth course having a mirror image of the fifth course, and wherein upon heating, the third yarn is a thermally fusible yarn which melts at the heated temperature and binds the adjacent yarns in the double convex structure.

In a further embodiment, the method wherein the first yarn is selected from the group consisting of: a monofilament yarn, a monocomponent monofilament yarn, and a multicomponent monofilament yarn.

In a further embodiment, the method wherein the first yarn has a higher modulus than the second yarn.

In a further embodiment, the method wherein the second yarn is a monocomponent multifilament yarn or a multicomponent multifilament yarn.

In a further embodiment, the method wherein after heating, the spacer fabric comprises a plurality of zones having different compression resistances in a thickness direction of the fabric defined by modifying the knit structure or the yarn in the different zones. In a further embodiment, the method wherein the spacer fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance. In a further embodiment, the method wherein the first zones have a compression resistance of no more than 30 psi and the second zones have a compression resistance of at least 50 psi.

In a preferred embodiment, a spacer fabric comprising: a knit structure formed from a first yarn having a low thermal shrinkage and a second yarn having a higher thermal shrinkage than the first yarn, wherein the first yarn comprises a knit and tuck pattern on a first course and a mirror image of the knit and tuck pattern on a second course, wherein the second yarn comprises a tuck and miss pattern on a third course and a mirror image on a fourth course, and wherein the mirror images of each of the first, second, third, and fourth courses are positioned on a front needle bed or a back needle bed; and wherein upon heating of the knit structure, the high shrinkage yarn shrinks to form a plurality of concave portions forming a sinusoidal shape in facing opposition to a plurality of opposing convex portions, the concave portions and the opposing convex portions defining void spaces having a substantially double convex cross section.

In a further embodiment, the spacer fabric wherein the knit structure is a unitary knit structure.

In a further embodiment, the spacer fabric wherein the second yarn shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C.

In a further embodiment, the spacer fabric wherein heating the knit structure at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension increases a size of the void spaces in a thickness direction of the fabric.

In a further embodiment, the spacer fabric wherein a thickness of the fabric increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.

In a further embodiment, the spacer fabric further comprising a third yarn, said third yarn being a thermally fusible yarn, wherein the thermally fusible yarn is positioned within a knit, tuck, or miss pattern on a fifth course and a mirror image on a sixth course, and wherein after heating of the fabric to a temperature sufficient to melt the thermally fusible yarn, the thermally fusible yarn melts and fuses with the first and second yarns.

In a further embodiment, the spacer fabric further comprising a knit transition zone.

In a further embodiment, the spacer fabric wherein a knit pattern comprises between 6 and 24 courses in one direction and between 6 and 48 needles in another direction to define the knit structure of the fabric.

In a preferred embodiment, a spacer fabric comprising: a knit structure formed from a first yarn having a low thermal shrinkage and a second yarn having a higher thermal shrinkage than the first yarn, wherein the first yarn comprises a knit and tuck pattern defined within a front needle bed, a back needle bed, or both on a first course and a mirror image of the knit and tuck pattern on a second course and wherein the second yarn comprises a tuck and miss pattern on a third course and a mirror image on a fourth course, wherein the mirror images of each of the first, second, third, and fourth courses are defined in relation to the front needle bed or the back needle bed of each course, and a third yarn, being a thermally fusible yarn, having a pattern comprised of knit, tuck, or miss stitches along a fifth course and a mirror image on a sixth course; and wherein upon heating of the knit structure, the high shrinkage yarn shrinks to form a plurality of concave portions in facing opposition to a plurality of opposing convex portions, the concave portions and the opposing convex portions defining void spaces having a substantially double convex cross section, and the thermally fusible yarn fuses the structure defined by the first, second, and third yarns.

These and other embodiments are described in greater detail in the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a perspective view of a spacer fabric according to one embodiment described herein.

FIG. 1B illustrates a perspective view of a spacer fabric according to one embodiment described herein.

FIG. 1C illustrates a perspective view of a spacer fabric according to one embodiment described herein.

FIG. 2 schematically illustrates a sectional view of a spacer fabric before and after carrying out a heating step according to one embodiment described herein.

FIG. 3 illustrates a perspective view of a spacer fabric before carrying out a heating step according to one embodiment described herein.

FIG. 4 illustrates a perspective view of the spacer fabric of FIG. 3 after carrying out a heating step according to one embodiment described herein.

FIG. 5 schematically illustrates a sectional view of a conventional weft knitted spacer fabric for comparison purposes.

FIG. 6 illustrates a perspective view of a conventional spacer fabric corresponding to the spacer fabric of FIG. 5 .

FIG. 7 is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 8 is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 9A is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 9B is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 9C is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 9D is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 9E is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

FIG. 9F is a needle diagram illustrating a method of knitting a spacer fabric according to one embodiment described herein.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments described herein can be understood more readily by reference to the following detailed description, examples, and figures. Elements, apparatus, and methods described herein, however, are not limited to the specific embodiments presented in the detailed description, examples, and figures. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the scope of the invention.

In addition, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1.0 to 10.0” should be considered to include any and all subranges beginning with a minimum value of 1.0 or more and ending with a maximum value of 10.0 or less, e.g., 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.

All ranges disclosed herein are also to be considered to include the end points of the range, unless expressly stated otherwise. For example, a range of “between 5 and 10,” “from 5 to 10,” or “5-10” should generally be considered to include the end points 5 and 10.

I. Methods of Making a Spacer Fabric

In one aspect, methods of making a spacer fabric are described herein which, in some cases, can provide one or more advantages compared to other methods. For example, in some instances, a method described herein can provide a spacer fabric that has improved compression resistance. A method described herein can also be used to make a spacer fabric having a plurality of zones of differing compression resistances. Moreover, the zones can correspond to a pressure map of the spacer fabric during use in an end application, such as a seating application or a footwear application. Further, a method described herein can provide a spacer fabric in a more efficient and/or cost-effective manner compared to some other methods.

A method of making a spacer fabric described herein, in some embodiments, comprises knitting a first yarn (or fiber) and a second yarn (or fiber) to form a knit structure, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions. The concave portions can be repeating portions, such that they form a wave-like or sinusoidal shape in a length or width direction of the knit structure. Similarly, the convex portions can be repeating portions, such that they form a wave-like or sinusoidal shape in a length or width direction of the knit structure, as described further below. Further, the concave portions and the convex portions together define void spaces having a substantially double convex cross section. More particularly, the concave portions and the convex portions can be aligned with one another, including in a one-to-one manner, such as may be caused by an offset in the sinusoidal shape or pattern formed by the plurality of concave portions and the sinusoidal shape or pattern formed by the plurality of convex portions. For instance, in some cases, each concave portion is mirrored by or aligned with a corresponding convex portion in facing opposition to the concave portion, thereby defining a double convex void space. It is to be understood that a “double convex” cross section or shape is a shape defined by two convex curves in a back-to-back configuration, such as in a double convex lens, as opposed to the configuration of a piano-convex lens or a concavo-convex lens. A “substantially” double convex cross section or shape refers to a cross section or shape that is essentially a double convex cross section or shape, but that may differ from such a shape by a de minimis amount, such as by having an “offset” from a back-to-back configuration of less than 5%, less than 3%, or less than 1%. Moreover, the knit structure of a spacer fabric described herein can be a unitary knit structure, as opposed to a knit structure formed by sewing, linking, or otherwise joining separate fabrics in a non-knitting manner.

Additionally, the first yarn (or fiber) used to form the knit structure is a low thermal shrinkage yarn (or fiber), and the second yarn (or fiber) is a high thermal shrinkage yarn (or fiber). It is to be understood that the terms “low” and “high” thermal shrinkage are relative to one another. In other words, the “low” thermal shrinkage yarn shrinks less in response to heating than the “high” thermal shrinkage yarn does. In some embodiments, the “high” thermal shrinkage yarn (or fiber) shrinks at least twice as much, at least three times as much, at least five times as much, or at least 10 times as much as the “low” thermal shrinkage yarn (or fiber) at a given temperature or other heating condition, in at least one dimension, where the amount of shrinkage of each yarn (or fiber) is a percent shrinkage based on the original dimension of the respective yarn (or fiber) at 25° C., prior to heating. In some instances, the high thermal shrinkage yarn (or fiber) shrinks 2-100 times, 2-50 times, 2-20 times, 2-10 times, 2-5 times, 2-4 times, times, 5-50 times, 5-20 times, 5-10 times, 10-100 times, 10-50 times, or 10-20 times as much in at least one dimension as the low thermal shrinkage yarn (or fiber) does at a given temperature or other heating condition. Moreover, in some preferred embodiments, the dimension of thermal shrinkage is a longitudinal or “length” direction of the yarn (or fiber), as opposed to a radial or “width” dimension of the yarn (or fiber). Alternatively, in some cases, thermal shrinkage (including differential thermal shrinkage as compared between the two yarns or fibers) occurs in a radial direction of a yarn (or fiber). In still other instances, the differential thermal shrinkage occurs in a radial direction as well as a longitudinal direction of the yarns (or fibers).

Turning again to steps of methods described herein, methods described herein, in some embodiments, further comprise heating the knit structure at a temperature sufficient to cause the second yarn or fiber to shrink in at least one dimension. In some cases, the second yarn or fiber shrinks by at least 10% in at least one dimension, where the percentage is based on an original size or length of the second yarn or fiber in the at least one dimension prior to the step of heating the knit structure. In some cases, the second yarn or fiber shrinks by at least 20%, at least 30%, or at least 40% in at least one dimension. In some embodiments, the second yarn or fiber shrinks by 10%-90% in the at least one dimension during the step of heating the knit structure. Additionally, it is to be understood that the second yarn or fiber shrinks more than the first yarn or fiber in the at least one dimension during the step of heating the knit structure. For example, in some cases, the first yarn or fiber shrinks by less than 10%, less than 8%, less than 5%, or less than 3% in the at least one dimension during the heating step, based on an original size or length of the first yarn or fiber in the at least one dimension prior to the step of heating the knit structure.

Further, in general, the step of heating the knit structure increases a size of the void spaces of the knit structure, particularly in a thickness direction or z direction of the fabric. A “thickness” direction of the fabric, for reference purposes herein, is orthogonal to the width and length directions (or x and y directions) of the fabric. Often, the “thickness” or z direction is the shortest dimension of the fabric, which may have much larger width (x) and length (y) directions. It is further to be understood that the z direction of the fabric can be generally orthogonal to the “direction of propagation” or “crest-to-crest direction” of the sinusoidal shapes or patterns formed by the plurality of concave portions and the plurality of convex portions. In some embodiments, the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 100%. In some cases, the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 200%, at least 300%, at least 400%, at least 500%, at least 700%, at least 900%, or at least 1,000%. In some instances, the size of the void spaces in the thickness direction of the fabric increases by 100%-5,000%, 100%-1,000%, 100%-900%, 100%-500%, 100%-300%, 200%-5,000%, 200%-1,000%, 300%-5,000%, or 300%-1,000%. Additionally, in some embodiments, the fabric is flat or substantially flat prior to heating, and raised or nonflat or “three-dimensional” after heating. In some instances, the thickness of the fabric increases by at least 0.5 cm, at least 1 cm, at least 2 cm, at least 3 cm, or at least 5 cm after heating. Other increases in thickness are also possible. A “substantially” flat fabric, for reference purposes herein, can be within 10%, within 5%, within 3%, or within 1% of being flat under standard temperature and pressure conditions (in particular IUPAC STP conditions), the percentage being based on an increase in thickness of the “substantially” flat fabric, as compared to an otherwise identical fabric that is “flat” under the standard temperature and pressure conditions.

Any yarns or fibers not inconsistent with the objectives of the present disclosure may be used to form the knit structure of a spacer fabric described herein. Further, it is to be understood that “yarns” or “fibers” as used hereinabove can refer collectively to fibers, yarns, and filaments. In some cases, for instance, a knit structure is formed from a single component yarn, a multicomponent yarn (such as a bicomponent yarn or a yarn having 3 components (i.e., a tricomponent yarn), a yarn having 4 components (i.e., a quadcomponent yarn), or a yarn having more than 4 components), or a combination thereof. A multicomponent yarn can have a sheath/core structure, a side-by-side structure, or an islands-in-the-sea structure. Other multicomponent yarn structures can also be used.

Further, in some embodiments, a knit structure is formed from a monocomponent monofilament yarn, a multicomponent monofilament yarn, a monocomponent multifilament yarn, a multicomponent multifilament yarn, or a combination thereof. A yarn used in a method described herein may also include separate filaments formed from different materials, or a plurality of filaments that are each formed from two or more different materials. It is also to be understood that a “yarn” such as a “first yarn” or a “second yarn” described herein can refer to a type of yarn, as opposed to simply a single yarn. Thus, for instance, use of “a first yarn” and “a second yarn” to provide a knit structure in a manner described herein is to be understood to refer to the use of one or more yarns of a first type (corresponding to “a first yarn”) and one or more yarns of a second type (corresponding to “a second yarn”).

In some preferred embodiments, the first yarn is a monofilament yarn. In some such instances, for example, the first yarn is a monocomponent monofilament yarn or a multicomponent monofilament yarn. In addition, in some cases, the first yarn has a higher stiffness or modulus than the second yarn. Additionally, in some embodiments, the second yarn is a multifilament yarn. For example, in some instances, the second yarn is a monocomponent multifilament yarn or a multicomponent multifilament yarn.

Moreover, in some cases, a knit structure described herein is formed from a third yarn in addition to the first yarn and the second yarn, the third yarn differing from the first yarn and the second yarn. Any third yarn not inconsistent with the objectives of the present disclosure can be used. For example, in some embodiments, the third yarn is a thermally fusible or heat-fusible yarn. In some cases, such a third yarn is fusible at the temperature of the step of heating the knit structure. Additionally, in some such instances, stable and elastic single component multifilament and/or monofilament yarns are used as the third yarns. In some cases, the yarns can be formed from low melting point polymers, such as polymers having a melting point below about 200° C., below about 150° C., below about 100° C., or below about 80° C. In some embodiments, the yarns can be formed from polymers having a melting point between about 80° C. and about 150° C. Such yarns can be heated, with or without pressure, to cause the low melting components to melt and flow, thereby modifying the physical properties of the knit structure, including by serving as an adhesive. In other cases, stable and elastic multicomponent (e.g., bicomponent) multifilament and/or monofilament yarns are used. In some such embodiments, the yarns can be formed from low melting polymers in combination with higher melting point polymers (such as polyester or nylon), such that the low melting polymer components but not the higher melting components of the yarns can be made to melt and flow by the application of heat with or without pressure, thereby modifying the physical properties of the knit structure in a desired manner, including by providing an adhesive element and/or structural support.

Further, in some embodiments, a knit structure described herein is formed from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn, wherein the fourth yarn differs from the first yarn, the second yarn, and the third yarn. Any fourth yarn not inconsistent with the objectives of the present invention can be used. Moreover, the fourth yarn can be used to provide desired performance features to a spacer fabric described herein, in addition to those described above. For instance, in some cases, the fourth yarn has a color, texture, denier, and/or elasticity that differs from a color, texture, denier, and/or elasticity of the first yarn, the second, yarn, and/or the third yarn.

As described above, a fiber, yarn, or filament or a portion of a fiber, yarn, or filament described here can comprise or be formed from any material not inconsistent with the objectives of the present invention. In some embodiments, for example, a fiber, yarn, or filament comprises or is formed from a synthetic material such as nylon or another polyamide, polyester, polyethylene, polypropylene, polybutylene, or another polyolefin, or polyacrylic. In other cases, a fiber, yarn, or filament comprises or is formed from a natural fiber material such as cotton, wool, or silk. Other fibers, yarns, and filament materials may also be used, such as regenerated cellulose or rayon. In certain cases, the fiber, yarn, or filament comprises or is formed from a rate-sensitive material, such as a rate-sensitive thermoplastic elastomer. Such materials are configured to exhibit different stiffness values at different frequencies or rates. For example, rate-sensitive materials can be soft, comfortable, and flexible at lower frequencies, but stiffen under higher frequencies for increasing the stability and performance. An exemplary rate-sensitive material is D30®, a DuPont™ Hytrel® thermoplastic elastomer.

In still other cases, the fiber, yarn, or filament comprises or is formed from a metallic material such as stainless steel, copper, or a metal mixture or metal alloy. In some instances, the metallic material is electrically conductive. Other electrically conductive fibers, yarns, or filaments may also be used. Such electrically conductive materials can be used, in some cases, for the dissipation of static charge and/or for the formation of “smart” or electrically integrated materials. For example, and in certain cases, formation of a smart material enables a spacer fabric constricted therefrom to provide diagnostics. Such diagnostics may include, for example, and without limitation, step-counting diagnostics, speed diagnostics, force or impact diagnostics, or any other type of diagnostic not inconsistent with objectives of the present invention. It is also possible for a fiber, yarn, or filament described herein to include or be formed from a shape memory material such as a shape memory polymer or a shape memory alloy. Other materials, such as pressure-chromic yarns may be used in the methods of forming the spacer fabrics described herein, for example, so that the spacer fabric is responsive or reactive to various changes or stimuli and, thus, varies in regard to the amount of stiffness or pressure provided by the fabric. Such fabrics may be used, for example, to massage the user's body (e.g., back, foot, etc.) when positioned adjacent or proximate to the spacer fabric.

A fiber, yarn, or filament described herein can also be coated with one or more additional materials to provide a desired property. In some cases, for instance, a fiber, yarn, or filament can be coated with a fluorocarbon such as polytetrafluoroethylene. A fiber, yarn, or filament described herein can also include one or more additives, including polymer additives, which can provide heat absorption and/or heat reflectivity properties, electrical conductivity and/or static dissipation properties, or low coefficient of friction properties. For example, such additives may be used to heat or cool the spacer fabric during use, such that the user's body (e.g., back, foot, etc.) may be heated or cooled during use via the spacer fabric. An additive can also be used to provide a “smart” fabric or textile. Nonlimiting examples of thermally conductive additives which may be used in some embodiments described herein include ceramics such as aluminum nitride and/or boron nitride ceramics, metals such as aluminum or copper, and nanoscale carbon materials such as carbon fibers, carbon nanotubes, and graphite nanoplatelets.

Additives comprising thermochromic or photochromic pigment and dye materials may also be used. Such pigment and dye materials can change color in response to heat or light. It is also possible to incorporate one or more antimicrobial or antifungal materials into or onto a fiber, yarn, or filament described herein, including for odor control. Nonlimiting examples of antimicrobial or antifungal materials that may be used in some embodiments described herein include inorganic, organic, and/or metal-containing antimicrobial materials such as materials comprising silver, copper, and/or zinc, and quaternary silane-based antimicrobial materials.

Moreover, a fiber, yarn, or filament described herein can have any size, shape, and/or denier not inconsistent with the objectives of the present invention.

In addition, a spacer fabric formed by a method described herein can comprise regions having the same or differing properties. For example, in some cases, a spacer fabric can have regions of the same or differing stability, rigidity, elasticity, support, softness, cover, durability against fraying, durability against unraveling, cushioning, compression, breathability, weight, density, color, water wicking ability, and/or water resistance. Further, the properties of a region of a spacer fabric described herein can be selected based on the type of knitting process, the type of stitch, and/or the chemical composition or type of fiber, yarn, or filament used to form the region. Thus, by selectively forming regions having differing properties, a spacer fabric can be provided that has both a unitary knitted structure and also complex features, varied regions, or features or regions selected for specific applications. The unitary structure can be formed by a single knitting operation according to a method described herein.

For example, a spacer fabric made by a method described herein can have one or more regions of high breathability (such as may be provided by the use of a meshed stitch structure), one or more regions of high elasticity (such as may be provided by the use of an elastomeric yarn), one or more regions of high rigidity (such as may be provided by the use of a non-elastomeric yarn), and/or one or more regions that can be further shaped using the heat treatment (such as may be provided by the use of a fusible yarn). In another instance, a spacer fabric made by a method described herein can include relatively soft regions and relatively abrasion resistant regions. A soft region may be located on one side (e.g., a user contacting side) of the spacer fabric, and an abrasion resistant region may be located on the other side (e.g., a nonuser contacting side) of the spacer fabric. Selectively varying the type of knitting process, the type of stitch, and/or the chemical composition or type of fiber, yarn, or filament used during a method escribed herein can also provide spacer fabric having desired aesthetic, design, or texture elements.

In some preferred embodiments, a spacer fabric described herein, after heating, comprises a plurality of zones having different compression resistances in a thickness direction of the fabric. For example, in some cases, the spacer fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance. It is to be understood that “low” and “high” compression resistance are relative to one another. For instance, in some embodiments, the first zones have a compression resistance of no more than 30 psi, no more than 20 psi, or no more than 10 psi, and the second zones have a compression resistance of at least 50 psi, at least 60 psi, at least 70 psi, at least 80 psi, or at least 100 psi. Moreover, in some cases, the locations of the first and second zones are determined based on a pressure map of the fabric when in use in an end application.

Spacer fabrics described herein can be used in any end application not inconsistent with the objectives of the present disclosure. Moreover, spacer fabrics described herein can be formed in a custom manner to meet the needs of a specific end use. Additionally, in general, a knit structure/spacer fabric described herein can have a definitive custom shape and dimension around the perimeter of the end product (e.g., the final fabric to be used in an end application) that is shaped on the knitting machine for the end use. In other words, the spacer fabric can be properly shaped for the end use without being cut or sewn. Thus, in some embodiments, a spacer fabric described herein is not cut or sewn, including for incorporation into a product or before incorporation into a product, such as a product described below.

In some cases, the end application of a spacer fabric described herein is a footwear application. A spacer fabric described herein, for example, can be used as a separate and removable insole of a shoe. A spacer fabric described herein may also be used to form a complete knit shoe upper with an integral spacer fabric sole/insole. In still other embodiments, a spacer fabric described herein can be used in footwear such as socks.

Additionally, the end application of a spacer fabric described herein can be an apparel application. For example, a spacer fabric described herein can be used in safety and sportswear components and garments, particularly components and garments in which cushioning regions may be desirable for impact resistance and protection in certain areas for force dampening from impact. As described above, spacer fabrics described herein can be configured to provide impact resistance in certain zones of the apparel, such as for use in high impact and dangerous sports such as football, cross country cycling and many others in which elbows, knees, hips, shins and skulls, and other bodily regions need cushioning from severe impact.

In other instances, the end application of a spacer fabric described herein is a seating application. For example, a spacer fabric can be used to form all or a portion of a chair back and/or seat for offices, homes, hospitals, wheel chairs, schools, automobiles, motorcycles, bicycles, lawn mowers, and other vehicles and devices. Further, such a seating component formed from a spacer fabric having differing zones, as described above, can help protect and support the body of a user from impact, including with reference to pressure mapping of the seating component when in use.

In still other embodiments, a spacer fabric described herein is used in bedding applications. For example, in some cases, a spacer fabric described herein can be used to provide a complete sleeping support surface, or to provide a component or element of a mattress. In some such instances, the spacer fabric can provide additional support and ventilation.

More generally, the three-dimensional structure of spacer fabrics described herein, which can include primarily void spaces/air as described above, without filaments extending between upper and lower surfaces, can facilitate or enable improved ventilation of the body of a user in contact with the spacer fabrics. Spacer fabrics described herein can also help maintain a user of the spacer fabrics at a desired temperature for the relevant end uses of the spacer fabrics.

Methods described herein can be carried out in any manner not inconsistent with the objectives of the present invention. For example, in some cases, a method described herein is carried out using a knitting machine. More particularly, in some embodiments, a method described herein is carried out using a weft knitting machine having at least two sets of needles. For example, in some instances, the knitting machine is a flatbed knitting machine having a front needle bed and a back needle bed. In other cases, the knitting machine is a circular knitting machine having a cylinder set of needles and a dial set of needles. In addition, a knitting machine used in a method described herein can be automated. For example, in some cases, a knitting machine is configured to carry out a knitting process according to needle-by-needle or stitch-by-stitch instructions provided by a computer as a function of space and/or time. The computer can include a processor and a memory storing computer-readable program code portions that, in response to execution by the processor, cause instructions to be provided to one or more components of a knitting machine in a desired sequence.

II. Spacer Fabrics

In another aspect, spacer fabrics are described herein. The spacer fabrics can be formed in any manner described in Section I hereinabove and can have any features or properties of spacer fabrics described hereinabove in Section I. In some embodiments, for example, a spacer fabric described herein comprises a knit structure formed from a first yarn and a second yarn, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section. Further, the first yarn is a low thermal shrinkage yarn, and the second yarn is a high thermal shrinkage yarn. Moreover, in some cases the knit structure is a unitary knit structure.

It is further to be understood that the first and second yarns of a spacer fabric described herein can have any properties, including any properties relative to one another, not inconsistent with the objectives of the present disclosure. For instance, as described above in Section I, in some embodiments, the second yarn of the spacer fabric shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C. Additionally, in some cases, heating the knit structure of the spacer fabric at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension increases a size of the void spaces in a thickness direction of the fabric, including in a manner described hereinabove. In some instances, a spacer fabric described herein, when unheated, is flat or substantially flat. Further, in some embodiments, a thickness of the fabric increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.

Returning again to yarns of spacer fabrics described herein, in some embodiments, the first yarn is a monofilament yarn, such as a monocomponent monofilament yarn or a multicomponent monofilament yarn. Other yarns may also be used as the first yarn. In addition, in some cases, the first yarn has a higher modulus than the second yarn. Further, in some embodiments, the second yarn is a multifilament yarn such as a monocomponent multifilament yarn or a multicomponent multifilament yarn. Other second yarns may also be used.

Moreover, in some embodiments, the knit structure of a spacer fabric described herein is formed from a third yarn in addition to the first yarn and the second yarn, the third yarn differing from the first yarn and the second yarn. Any third yarn not inconsistent with the objectives of the present disclosure may be used, including a third yarn described hereinabove in Section I. For example, in some cases, the third yarn is a thermally fusible yarn, such as a third yarn that is thermally or heat-fusible at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension.

Similarly, in some cases, the knit structure of a spacer fabric described herein is formed from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn of the knit structure, wherein the fourth yarn differs from the first yarn, the second yarn, and the third yarn. Any fourth yarn not inconsistent with the objectives of the present disclosure may be used, including a fourth yarn described hereinabove in Section I. In some embodiments, for instance, the fourth yarn has a color, texture, denier, and/or elasticity that differs from a color, texture, denier, and/or elasticity of the first yarn, the second, yarn, and/or the third yarn.

Additionally, as described above in Section I, a spacer fabric described herein can comprise a plurality of differing zones, the zones having one or more differing properties. For example, in some cases, the fabric comprises a plurality of zones having different compression resistances in a thickness direction of the fabric. In some such embodiments, the fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance, such as one or more first zones having a compression resistance of no more than 30 psi and one or more second zones having a compression resistance of at least 50 psi. As described above, the locations of such zones, in some instances, correspond to a pressure map of the fabric when in use in an end application, including an end application described above.

Moreover, as described above in Section I, a spacer fabric described herein can be used in a variety of end use applications. For example, in some embodiments, a spacer fabric described herein forms a portion of a seat or seat back. In other cases, a spacer fabric described herein forms a portion of footwear.

Some embodiments described herein are further illustrated in the following nonlimiting examples.

EXAMPLES

As described above, disclosed herein are nonconventional, innovative ways of making three-dimensional weft knit spacer fabrics, either as continuous lengths of fabrics, panels or in different custom shapes such as for footwear insoles or chair seat and/or back panels as a cushioning/support member.

Several different textile yarns were generally used to produce spacer fabrics according to some embodiments described herein. A minimum of two (A+B), and more preferably three (A+B+C) material yarns were used in the following examples. Additional types of yarn could be added for color, texture, or other aesthetic or performance properties if desired, as described above.

Yarn A

This yarn type was used to make up the rigid skeleton portion of the spacer fabric, which provides one of two important elements of the 3D structure and cushioning of the fabric. This yarn A was typically a stiff higher modulus monofilament yarn that provides the primary stiffening agent in the fabric and the knit construction. Together with the yarn composition and modulus of the yarn as well as subsequent heat setting, these features all work together to provide the major contributors to the fabric's compressive resistance.

Yarn A, in some cases, is as follows:

-   -   A1. Monocomponent monofilament, or     -   A2. Multicomponent (e.g., biocomponent) monofilament.

Typical polymers could be based on polyester, polyamide, polypropylene (or other polyolefins), and other melt processing polymers that can be extruded into monofilament yarns. The multicomponent monofilament yarn(s) could have a lower melting sheath material on the external coating of the yarn which would melt and flow to the adjacent yarns when the knitted fabric is heated after the knitting operation.

Yarn B: High Shrinkage Yarns

These yarns make up a second important component for the outer layer or skin of the fabric which reinforces and holds the skeleton in place due to the differential shrinkage as compared to yarn A. The differential thermal shrinkage between yarn A and yarn B together with the knit construction causes the flat fabric, as knit, to form the thicker 3D structure after the fabric is removed from the knitting machine and is subjected to heat.

Yarns of the yarn B type can typically be multifilament yarns for softness, high coverage, and easier knitting. But monofilaments could be used as well.

Type B yarns can be of different types, such as:

-   -   B1. Monocomponent monofilament,     -   B2. Multicomponent (e.g., bicomponent) monofilament,     -   B3. Monocomponent multifilament, or     -   B4. Multicomponent (e.g., bicomponent) multifilament.

Typical polymers can be based on polyester, polyamide, polypropylene (or other polyolefins), and other melt processing polymers that can be extruded into multifilament yarns.

Yarn C: Fusible Yarns

These (optional) yarns have a low melting point and can serve as bonding materials to keep the fabric from losing form and improve memory (resistance to permanent deformation due to cyclic compressive loading).

These yarns can be of different types, such as:

-   -   C1. Low shrinkage monocomponent monofilament     -   C2. Low shrinkage multicomponent (e.g., bicomponent)         monofilament     -   C3. High shrinkage monocomponent monofilament     -   C4. High shrinkage multicomponent (e.g., bicomponent)         monofilament     -   C5. Low shrinkage monocomponent multifilament     -   C6. Low shrinkage multicomponent (e.g., bicomponent)         multifilament     -   C7. High shrinkage monocomponent multifilament     -   C8. High shrinkage multicomponent (e.g., bicomponent)         multifilament

As described above, weft knit spacer fabrics described herein can be made on any weft knitting machine with a minimum of 2 sets of needles in either (FNB+BNB for flatbed machines, or cylinder and dial for circular weft knitting machines), and on any machine gauge, typically ranging from 5 gauge to 18 gauge (the number refers to the needles per inch in each of the respective needle beds). The gauges can be even finer if the knitting process is run on circular machines (the larger the number, the finer the gauge).

The yarn sizes can be based on the gauge of the equipment used to form the fabric. For example, on a 6.2 machine (12 gauge) the low shrinkage yarns could range from approximately 450 den to 1,400 den, and the high shrinkage and fusible yarns could range from 50 den to 1,200 den.

As described further herein, the knitting process in example embodiments described herein can be considered to comprise mirroring concave and convex structures made of the low shrinkage monofilament yarn, and then knitting the high shrinkage and fusible yarns in a similar fashion to cover the skeleton.

Different fabric patterns were accomplished using this technique, such as the fabric patterns illustrated in FIGS. 1A-1C. Each spacer fabric (100A, 100B, and 100C) illustrated in FIGS. 1A-1C was knitted from at least a first yarn and a second yarn to form the knit structures (which may also be denoted as [100A, 100B, and 100C]). The knit structures include various portions, regions, or zones (102). Additionally, the knit structures comprise or are formed from a plurality of opposing concave and convex portions that define a plurality of void spaces (106). FIG. 1A is a perspective view of a first spacer fabric (100A) comprising a plurality of repeating diamond shapes or patterns (102). Similarly, FIG. 1B is a perspective view of a second spacer fabric (100B) comprising a plurality of ribs (102), and FIG. 1C is a third spacer fabric (100C) comprising a plurality of repeating rectangular shapes or patterns (102). Other patterns can also be accomplished and are contemplated herein.

FIG. 2 is a schematic illustration of a sectional view of a spacer fabric according to some embodiments described herein. FIG. 2 illustrates both a preprocessed spacer fabric (200A) and a postprocessed spacer fabric (200B). The postprocessed spacer fabric (200B) has been heated to a temperature sufficient to shrink the high-shrinkage and fusible yarns forming the fabric. As indicated above, yarn types B and C are high shrinkage yarns that shrink more than the lower shrinkage yarn type A.

FIG. 3 is a sectional view of a spacer fabric (300) before heating. The fabric comprises a plurality of voids (302) formed therein, such voids being disposed or positioned between a first, upper portion (304A) and a second, lower portion (304B) of the fabric, which faces the first portion. The respective upper and lower portions (304A and 304B) of fabric are configured to form or define opposing concave and convex portions. FIG. 4 is a sectional view of the spacer fabric of FIG. 3 , denoted as (400) in FIG. 4 , after heating in a manner described hereinabove in Section I. As FIG. 4 illustrates, the plurality of void spaces (406) form and maintain a substantially double convex cross section during and after heating via shrinkage of the higher shrinkage yarn. The void spaces (406) are formed in the fabric (400) between the respective upper and lower portions (404A and 404B) of fabric.

Methods of making a spacer fabric described herein can provide fabrics that are very stable, as opposed to conventional weft knitted spacer fabrics, which tend to collapse on the wale direction (see FIGS. 5 and 6 for illustrations of conventional spacer fabrics, for comparison with FIGS. 2-4 ).

FIG. 5 is a schematic illustration of a sectional view of a conventional weft knitted spacer fabric (500) for comparison purposes. The fabric (500) includes orthogonally disposed lower shrinkage yarns (502) and higher shrinkage yarns (504), the lower shrinkage yarns (502) being prone to collapsing between the higher shrinkage yarns (504). FIG. 6 is a sectional view of a conventional spacer fabric (600) which has z direction yarns in the space (606) defined between the respective upper and lower faces (602, 604) of the overall spacer fabric.

Spacer fabrics according to some embodiments of the present invention have been formed that have load bearing capabilities (compressive resistance) ranging from about 4 psi to over 88 psi. As described further herein, the compressive resistance of a specific spacer fabric (or zone or region of a spacer fabric) can be selected based on one or more of the following:

-   -   (1) Yarn “A” material composition (e.g., choice of polymer)     -   (2) Yarn “A” processing (e.g., coating)     -   (3) Yarn “A” type (e.g., multicomponent versus monocomponent)     -   (4) Yarn “B” material composition     -   (5) Yarn “B” type (e.g., multicomponent)     -   (6) Yarn “C” presence or absence, and material composition and         type     -   (7) Knit construction (see below for examples of different knit         constructions according to various embodiments described herein)         and     -   (8) Heat setting conditions (e.g., time and temperature).

FIGS. 7 and 8 illustrate various “needle diagrams” for forming spacer fabrics according to some embodiments described herein. FIG. 7 is a needle diagram corresponding to an 11×11 needle tubular rib pattern. FIG. 8 is a needle diagram corresponding to an 11×11 needle tubular squares pattern. FIGS. 9A-9F are additional needle diagrams showing variations of the methods described herein.

In FIGS. 7-9 , rows of needles correspond to steps in specific knitting processes, where stitches on needles are shown. Additionally, certain rows of needles are marked with the type of yarn used (e.g., as yarn of yarn A type or yarn B type). Additionally, it is understood that not every row is so marked. However, as persons skilled in the art will appreciate, the type of a given row can be determined based on repetition of the identified patterns (e.g., repeating ribs, diamonds, squares, rectangles, etc.). In the following examples, though it differs from the general description above, the “A yarn” is a high shrink yarn, the “B yarn” is a lower shrink yarn than the A yarn, and the “CB yarn” is a fusible yarn.

In greater detail, one of ordinary skill in the art would understand the specifics of the needle diagram of FIGS. 7-9 . Beginning with FIG. 7 , a repeating plan of 12 courses, having 22 needles in both the front needle bed (FNB) and also the back needle bed (BNB), is depicted and repeating, as shown along the center line, repeating on needles 1-22 again. Notably, the diagram details a pattern of 12 horizontal rows, which can be repeated, as detailed on the left. Each repeat is a 12 course by 22 face needle plus 22 back needle repeat for a total of 44 needles so that the face and back are essentially identical. At course 1, the front and back needle beds are depicted. In course 1, the yarn is going to be missing a tucking, meaning that when it misses and tucks, on a rib fabric, it is only going to be on the inside, not on the outside or visible portions of the knit fabric. The first two needles are missed on each of the front and back bed, and tucks are stitched on the back bed on the 3rd needles of the back bed, and the 5th and the 7th, and then 9th. And then it continues to miss on the front and back bed for the tenth to fourteenth needle beds, and then it is tucking on the front needle bed on the 14th, 16th, 18th, and needles of the front bed, and missing on needle beds 21 and 22 on both the front and back beds. The centerline shows one repeat on the width direction. Just to the right of this line, is a repeat of the first set showing needles 1-22 again. Courses 1 and 2 are identified as using the “A” yarn, which is the high shrink yarn, which allows the tuck and miss structure to shrink greater than the other yarns, forming the desired blister pattern.

Course 2 provides a mirror image of course 1 and depicts missing on the front and back needle beds of first two needles of the FNB and BNB, and then forming a tuck stitch on the 3rd, 5th, 7th, 9th needles on the front bed. This follows that tucking on the back bed occurs on the 14th, 16th, 18th, and 20th needles.

Moving to course 3, using a “B” yarn, and depicting the formation of knitting stitches and miss stitches. Course 3 is missing on the first needle of the front and back beds, and is forming a knitted stitch on the 2nd, 4th, 6th, 8th, and 10th of the front bed. And then on the 13th, 16th, 17th, 19th, and 21st of the back bed. We then repeat that pattern again. The B yarn is a lower shrink yarn than the A yarn.

Course 4 parallels that of course 3, where the knitted stitches are offset by one needle as compared to course 3. Notably, the yarn utilized in course 4 is noted as a C8 yarn, thus differing, for example, from the B yarn and A yarns of prior courses. This yarn can be any of a different color to a different material or have different properties, such as a melt yarn, which binds together the spacer fabric, as a nonlimiting example. Thus, course 4 details a knit stitch on the 1st, 3rd, 5th, 7th, 9th, and 11th needles of the front bed and also on the 12th, 14th, 16th, 18th, 20th, and 22nd needles of the back bed.

Comparing course 3 to course 4, the stitch pattern is conserved, except that they are offset by one needle bed. Then courses 5 and 6 are the mirror images of those of courses 3 and 4. The knitting structure, combined with the tuck and miss structure of courses 1 and 2, once shrunk, allows for the formation of the double convex structure defined herein. By alternating between the front and back bed, we are creating the blister pockets. When we apply the heat, the high shrinkage yarns contract in the width (if it were 1 meter wide it might shrink to 700 cm, due to high contraction of the high shrink yarn, and the fusible yarn would then lock the knitting stitch into the double convex consideration that was forced to bubble out due to the shrinkage of the A yarns.

Course 5 is a mirror image of course 3, while course 6 is a mirror image of course 4. Courses 3-6 only form knit and miss stitch on the needles of the front and back bed. While this is performed on 22 needles, this could be used on a different needle number, nonlimiting examples including 16,20, or 30 needles, and other sizes as understood by those of ordinary skill in the art. One could also increase the number of courses of tuck and miss (as in courses 1 and 2). Or increase the number of knit courses (as in courses 3-6). Those of ordinary skill in the art will recognize that the size of the blister will be shorter or longer up and down the fabric as you change the orientation and number of needles in the repeat and/or courses using tuck and miss or miss and tuck stitches.

Courses 7-12 now are the mirror image of those corresponding to courses 1-6. This is forming the opposing structures of the double convex. Where a traditional blister stitch has one flat side and has one that has the convex portion, we are doing it so that both sides face and back of the fabric have essentially the same size and shape and 3D effect the blister off of the centerline of the fabric prior to heating the fabric and causing differential shrinkage between the high and low shrink yarn components. Thus, either the front or the back needle sides could be considered the face of the fabric. Then by incorporating into the material a melt yarn, upon application of heat, and melting of the yarn, the melt yarn locks the double convex pockets or structures into place to create the more robust blistering pockets that will resist compression. Where, traditional blister stitch has one flat surface, and the blistering would be on one surface (where the blistering is the face surface), support is provided by the flat surface. In such an example, one would not use fusing or bonding yarns in structures with only a single blister face. Instead, the knit patterns of the present disclosure and the opposing structural knit pattern create the double convex pattern, which can be locked into place by a melt-fusible yarn. Finally, in the existing blister materials, having one flat face, you would not have both high and low shrink yarns on both faces. Again, it is the use of mirror image knitting that creates the pockets on each side of the material.

With regard to the particular knit pattern in FIG. 7 , the number of tuck and miss stitches, or miss and knit stitches can be a greater number than is depicted in FIG. 7 . For example, if we want to make a wider blister, instead of 5 and 5 on the back bed we can make a pattern such as depicted in FIG. 9D, that uses 10 knit stiches in a row. Such modifications of the number of courses, the number of stitches, etc. will modify the amplitude of the opposing convex blisters, so long as the mirror image pattern of these figures is conserved.

FIG. 8 , generally details an analogous needle pattern to FIG. 7 , except that it includes a transition section of the knit material. The transition means we are adding knit structures to move the pockets formed, or to close off the pockets so that they are not simply long tubes within the knit material. Thus, as noted in FIG. 8 , a “square A” or structure can be repeated before the transition section, and then a subsequent variation, can be utilized to form the second pattern or “square B”, which can also be repeated, before another transition section. This allows for the creation of different designs or different configurations.

FIG. 9A depicts a small knit structure that would fit within a larger repeated pattern, as detailed, one repeat is a 12-course repeat by 44 needles, 22 on the FNB plus 22 on the BNB, and could be repeated as desired. The knit pattern would make a “tubular rib” that would make two tubular ribs side by side. The miss and tuck structure of courses 1-2 follows the pattern where they are mirror images of one another, and with courses three and four differing with course three having five knit stitches and course four having six knit stitches, which are offset by one needle. Courses five and six then mirror those of courses three and four. FIG. 9B is highly similar to FIG. 9A and shows that the particular course can be switched, from front to back beds, so long as the symmetry is maintained in a subsequent course. Thus, the knit pattern to form the desired knit structure utilizes a pattern where there is symmetry between courses, such that courses three and five for FIG. 9A and courses three and six for FIG. 9B are mirror images. It is not material that the directly adjacent course is a mirror image, only that the knit structure uses the mirror image so as to form the knit pockets on both sides of the material.

FIG. 9C depicts a variation where instead of a 22-needle pattern, a 20-needle pattern is utilized, with a 16-course pattern. Course 1 is miss and tuck: front tucks on needles 4, 6, and 8 and also tucks on the back bed of needles 14, 16, and 18. Course 2 is creating knit stitches on needles 5, 7, and 9 of the front bed and also creating knit stitches on needles 15, 17, and 19 of the back bed. Course 3 the tuck stiches are on the opposite need bed side of the knit stiches of course 2. Where we form a tuck stitch on 4/6/8, the knitted stitches are on the 5/7/9. Thus, as compared to earlier details, the tuck and miss courses do not need to be directly adjacent to one another as long as the mirror image is contained so as to yield the desired structure. Here, adding in a knit stitch to courses two and four will yield an additional pattern and structure to the desired pockets on each side of the material.

Accordingly, FIG. 9D shows a different pattern, showing that the two rows of tuck and miss do not have to be adjacent to one another. The final yield will make a similar pattern as prior figures, but not identical. However, this will still form the two opposing pockets created without having courses 1 and 2 be tuck and miss. The knit pattern still comprises two courses of tuck and miss, just they are not directly adjacent to one another, they are separated by one course of miss and knit stiches.

FIG. 9D details a 10×10 tubular rib spacer knit, with a twelve-course repeat by 20-needle repeat. Notably, FIG. 9D shows that different knit patterns can be used with more knit stitches on the front or back needle beds, so long as they still contain the opposing structure in another course. Here, courses three and four are mirror images, and courses five and six are mirror images with the tuck stitches. Such pattern, having more consecutive knit stitches will change the shape of the double convex structure pocket created as well as have differing stretch or elastic properties.

FIGS. 9E and 9F add a further variation to the knit pattern, where courses contain both knit stitches and tuck stitches. Course three has its mirror image as course nine, and courses four and six again show both the knit and tuck stitches. Thus, while the particular knit pattern is different than prior examples, having a mirror image of one course is conserved.

In FIG. 9F, a further iteration is provided, for example, courses one and two show mirror image patterns using knit, tuck, and miss stitches on the needles. Whereas courses four and six remain with the same knit, tuck, and miss structures as in FIG. 9E.

Here, with courses one and two, the “A yarn” is the high shrink yarn and thus shrinks for both in the knit stitches and the tuck and miss stitches. Thus, high shrink yarns can also be used for knit structures. Furthermore, where the C8 yarn is a melt yarn, it would allow for both the knit structure and the tuck and miss to use this binding fiber, which will melt after heated. Such binding will lock the structure of the opposing convex pockets on both sides of the knit material.

In each of the knit diagrams, the pattern of having equal or nearly equal structures knit on the front and back needle beds (mirror images of one another), defines the double convex structure that is defined herein. Each of the knit diagrams show short, repeating sections of the knit structure. We need to have balance, within a short area of courses and also needles of the two needle beds, so as to create the interlocking pockets having the double convex structure as defined herein. Furthermore, the structures can then be defined within a pattern in the knit structure by incorporating a transition, as defined by FIG. 8 , which allows the knit structure to pause the double convex pockets so as to create closed pockets which have a double convex cross section in both length and width. Absent transitions, the double convex shape would extend along the length of the knit structure, until such transition terminates the open structure. Accordingly, symmetry with the shrinkage yarns and symmetry and balance for the low shrink yarns is important for defining the desired structure.

Various embodiments of the present invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the scope of the invention. 

What is claimed is:
 1. A method of making a spacer fabric comprising: knitting a first yarn and a second yarn to form a knit structure, the first yarn defining a knit and tuck pattern on at least a first course and a mirror image pattern on at least a second course and the second yarn defining a knit and miss pattern on at least a third course and a mirror image on at least a fourth course, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section, and wherein the first yarn is a low thermal shrinkage yarn and the second yarn is a high thermal shrinkage yarn; and heating the knit structure at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension wherein the second yarn shrinks more than the first yarn in the at least one dimension during the step of heating the knit structure.
 2. The method of claim 1 wherein the second yarn shrinks by 10% to 90% in the at least one dimension during the step of heating the knit structure based on an original size of the second yarn in the at least one dimension prior to the step of heating the knit structure.
 3. The method of claim 1 wherein the second yarn shrinks at least two times as much as the first yarn in the at least one dimension during the step of heating the knit structure.
 4. The method of claim 1 wherein the step of heating the knit structure increases a size of the void spaces in a thickness direction of the fabric.
 5. The method of claim 1 further comprising at least a third yarn, said at least third yarn defined in at least a fifth course having a knit, miss, or tuck pattern and at least a sixth course having a mirror image of the fifth course, and wherein upon heating, the third yarn is a thermally fusible yarn which melts at the heated temperature and binds the adjacent yarns in the double convex structure.
 6. The method of claim 1 wherein the first yarn is selected from the group consisting of: a monofilament yarn, a monocomponent monofilament yarn, and a multicomponent monofilament yarn.
 7. The method of claim 1 wherein the first yarn has a higher modulus than the second yarn.
 8. The method of claim 1 wherein the second yarn is a monocomponent multifilament yarn or a multicomponent multifilament yarn.
 9. The method of claim 1 wherein after heating, the spacer fabric comprises a plurality of zones having different compression resistances in a thickness direction of the fabric defined by modifying the knit structure or the yarn in the different zones.
 10. The method of claim 9 wherein the spacer fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance.
 11. The method of claim 10 wherein the first zones have a compression resistance of no more than 30 psi and the second zones have a compression resistance of at least 50 psi.
 12. A spacer fabric comprising: a knit structure formed from a first yarn having a low thermal shrinkage and a second yarn having a higher thermal shrinkage than the first yarn, wherein the first yarn comprises a knit and tuck pattern on a first course and a mirror image of the knit and tuck pattern on a second course, wherein the second yarn comprises a tuck and miss pattern on a third course and a mirror image on a fourth course, and wherein the mirror images of each of the first, second, third, and fourth courses are positioned on a front needle bed or a back needle bed; and wherein upon heating of the knit structure, the high shrinkage yarn shrinks to form a plurality of concave portions forming a sinusoidal shape in facing opposition to a plurality of opposing convex portions, the concave portions and the opposing convex portions defining void spaces having a substantially double convex cross section.
 13. The spacer fabric of claim 12 wherein the knit structure is a unitary knit structure.
 14. The spacer fabric of claim 12 wherein the second yarn shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C.
 15. The spacer fabric of claim 12 wherein heating the knit structure at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension increases a size of the void spaces in a thickness direction of the fabric.
 16. The spacer fabric of claim 12 wherein a thickness of the fabric increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.
 17. The spacer fabric of claim 12 further comprising a third yarn, said third yarn being a thermally fusible yarn, wherein the thermally fusible yarn is positioned within a knit, tuck, or miss pattern on a fifth course and a mirror image on a sixth course, and wherein after heating of the fabric to a temperature sufficient to melt the thermally fusible yarn, the thermally fusible yarn melts and fuses with the first and second yarns.
 18. The spacer fabric of claim 12 further comprising a knit transition zone.
 19. The spacer fabric of claim 12 wherein a knit pattern comprises between 6 and 24 courses in one direction and between 6 and 48 needles in another direction to define the knit structure of the fabric.
 20. A spacer fabric comprising: a knit structure formed from a first yarn having a low thermal shrinkage and a second yarn having a higher thermal shrinkage than the first yarn, wherein the first yarn comprises a knit and tuck pattern defined within a front needle bed, a back needle bed, or both on a first course and a mirror image of the knit and tuck pattern on a second course and wherein the second yarn comprises a tuck and miss pattern on a third course and a mirror image on a fourth course, wherein the mirror images of each of the first, second, third, and fourth courses are defined in relation to the front needle bed or the back needle bed of each course, and a third yarn, being a thermally fusible yarn, having a pattern comprised of knit, tuck, or miss stitches along a fifth course and a mirror image on a sixth course; and wherein upon heating of the knit structure, the high shrinkage yarn shrinks to form a plurality of concave portions in facing opposition to a plurality of opposing convex portions, the concave portions and the opposing convex portions defining void spaces having a substantially double convex cross section, and the thermally fusible yarn fuses the structure defined by the first, second, and third yarns. 